Saturday, 8 May 2010

Fatally flawed: Bollinger's circumcision death calculations

Dan Bollinger (of the International Coalition for Genital Integrity) has published "LOST BOYS: AN ESTIMATE OF U.S. CIRCUMCISION-RELATED INFANT DEATHS". In it, he claims that circumcision causes 117 deaths per year in the United States. It's a lengthy paper, and is frankly rather tedious to wade through, but I thought it might be interesting to see how he derived his estimate:

Though the data previously cited are insufficient to establish a definitive death rate on their own, there is enough available information to calculate an estimate. Not all of the reported 35.9 deaths out of 1,243,392 circumcisions can be attributed to related causes.

(Here Bollinger references a figure he has provided previously: "Hospital discharge records reveal that, during the 1991–2000 decade, on average 35.9 boys died from all causes each year during their stay (average 2.4 days) in the hospital in which both their birth and circumcision occurred (Thompson Reuters, 2004).")

What portion, then, is circumcision-related and how may we extrapolate to the number of deaths after hospital release? What we can safely assume is that it is unlikely that any of these infants would have been subjected to the unnecessary trauma of circumcision if they had been in critical condition, or that they would have been circumcised after their death.

This is indeed a relatively safe assumption, though it is not one that actually gets us any closer to an answer.

Gender-ratio data can help extrapolate a figure. Males have a 40.4% higher death rate than females from causes that are associated with male circumcision complications, such as infection and hemorrhage,4 during the period of one hour after birth to hospital release (day 2.4), the time frame in which circumcisions are typically performed (CDC, 2004). Assuming that the 59.6% portion is unrelated to gender, we can estimate that 40.4% of the 35.9 deaths were circumcision-related. This calculates to 14.5 deaths prior to hospital release.

This is extraordinary! Bollinger is, in effect, assuming that the difference between male and female death rates is due entirely to circumcision. But it is a well-established fact that male babies are more susceptible to deaths than females, and there is no evidence that this is due to circumcision. Indeed, if circumcision alone were responsible for the difference, then we might expect countries with low circumcision rates to have the same infant mortality rates among males and females. But in fact, that's not the case, as the following table shows:

Clearly, infant mortality rates are consistently higher among males regardless of circumcision rates. So Bollinger's approach is clearly flawed. When he is trying to estimate the risk due to circumcision he is actually estimating the risk due to being male!

But it gets even worse (this would be laughable if the subject weren't so serious). Even if we assume that Bollinger's method is sane and appropriate (in spite of evidence to the contrary), he manages to miscalculate those attributable to being male. If the rate is 40.4% higher among males then the observed rate (35.9) will be the rate in females plus 0.404 times that rate again (or 1.404 times the rate in females). So, to find the rate in females:

1.404f = 35.9

f = 35.9 / 1.404 = 25.57

And so the rate attributable to being male will be 40.4% of that, which is 10.33.

But, as noted, this is the rate attributable to being male, not to circumcision.

But as is often the case with hemorrhage and infection, some circumcision-related deaths occur days, even weeks, after hospital release. The CDC’s online searchable database, Mortality: Underlying cause of death, 2004 (CDC), lists causes by various age ranges and reveals that the percentage of deaths after release, compared with deaths before, is 772% greater. This ratio is comparable to Patel’s (1966) 700% postrelease infection rate.

Bollinger expresses this with less than optimal clarity, but what he seems to be saying is that the ratio between deaths in the hospital stay (which Bollinger identifies as typically 2.4 days) and those after the hospital stay (but presumably within the first 28 days of life) is 7.72.

Frankly, that shouldn't be surprising. There are 10.7 times as many days in the latter period than there are in the former, so one would ordinarily expect more deaths simply due to there being more time in which people can die.

Multiplying the 772% adjustment factor for age-at-time-of-death by the 14.5 hospital-stay deaths calculated above, the result is approximately 112 circumcision-related deaths annually for the 1991–2000 decade, a 9.01/100,000 death-incidence ratio.

This multiplication is irrational. It stands to reason that there would be more deaths in the first 28 days than the first 2.4 days, simply because there is more time in which infants can die. If we look at the first 100 years of life, then the ratio will be even greater (in fact, the mortality rate over that period will be almost 100%), but would it make any sense to apply that ratio? Of course not — people die of other things than circumcision, and it wouldn't make any sense.

It doesn't make sense to apply this multiplication, either. Yes, a certain number of circumcision-related deaths will likely occur some time after the event, but it doesn't make any sense to assume, in effect, that any deaths in the period must be due to circumcision.

Applying this ratio to the 1,299,000 circumcisions performed in 2007, the most recent year for which data are available (HCUP, 2007), the number of deaths is about 117. This is equivalent to one death for every 11,105 cases, which is not in substantial conflict with Patel’s observation of zero deaths in 6,753 procedures. It is more than someother estimates (Speert, 1953; Wiswell, 1989),

It is perhaps a little disingenuous to refer to these as "estimates". These are observations showing 1 death in 566,000 circumcisions (Speert), no deaths in 100,000 boys (Wiswell). Similarly, King reported no deaths in 500,000 circumcisions. So if we use 1 in 500,000 as a reasonable estimate, we would expect 2.6 deaths in 1.3 million circumcisions. Bollinger's errors have led him to a figure some 45 times greater than that which can be extrapolated from actual statistics!

but less than the overstated 230 figure derived from Gairdner (1949). Breaking this statistic down further, about 40% of these deaths (47) would have been from hemorrhage, and the remainder (70) from sepsis, using a hemorrhage-to-sepsis ratio for infant mortality (NCHS, 2004).

Yes, I suppose the nice thing about imaginary numbers is that there is an inexhaustible supply of them.

24 comments:

How many deaths from a non-therapeutic procedure performed without consent are acceptable?

Well, one has to weigh the deaths due to circumcision against the number prevented. After all, circumcision prevents a certain number of cases of UTI, HIV, and penile cancer, and a certain (albeit small) fraction of these cases will be fatal. The evidence suggests that more deaths will be prevented than caused — for example, Wiswell and Geschke reported two deaths in 36,000 uncircumcised boys during the first month of life, and none in 100,000 circumcised boys in the same time frame.

It has come to my attention that the title of my post ("Fatally flawed...") could be interpreted as word play in rather poor taste. It's a little late to change, but I assure readers that this was unintended.

^^ Wiswell and Geschke reported two deaths in 36,000 uncircumcised boys during the first month of life ^^

Naturally I'm not persuaded by Wiswell and Geschke that two deaths would have been avoided by performing amputations of those boys perfectly evolved pleasure-receptive tissue.

There has never been a study to properly weigh the effect of care-giver education (i.e. no fiddling with the foreskin) on UTI incidence.

I certainly don't care about STDs when it comes to over-riding a child's right to bodily integrity and his right to decide how to thwart STDs.

And of course cancer in the penis is a treatable affliction of old men who've had a lifetime to enjoy their intact bodies. Whatever circumcision's effect, the existance of whole non-circumcising cultures with lower cancer rates than the mostly-cut US proves that circumcision is neither neccessary nor sufficient to prevent cancer. Cancer of the penis is strongly associated with HPV, for which there is now a vaccine.

Which other supposed threats from being intact will be dealt with by the time today's infant can grow and make his own rational choice based on the best info then available?

"The evidence suggests that more deaths will be prevented than caused — for example, Wiswell and Geschke reported two deaths in 36,000 uncircumcised boys during the first month of life, and none in 100,000 circumcised boys in the same time frame."

That "Crash!" you heard was the sound of Jake's statistical credibility flying out the window. I doubt that even Wiswell used that weak correlation to imply that circumcision saved those lives.

Naturally I'm not persuaded by Wiswell and Geschke that two deaths would have been avoided by performing amputations of those boys perfectly evolved pleasure-receptive tissue.

As you wish. I'm just supplying the evidence. You can do with it as you see fit.

There has never been a study to properly weigh the effect of care-giver education (i.e. no fiddling with the foreskin) on UTI incidence.

True, but given that the protective effect is observed in many different settings (including among adults), it seems doubtful that it could be explained by caregivers "fiddling" with the foreskin.

I certainly don't care about STDs when it comes to over-riding a child's right to bodily integrity and his right to decide how to thwart STDs.

I thought we were discussing numbers of deaths, not whether you cared about them?

And of course cancer in the penis is a treatable affliction of old men who've had a lifetime to enjoy their intact bodies.

Are you saying that these deaths don't matter?

Whatever circumcision's effect, the existance of whole non-circumcising cultures with lower cancer rates than the mostly-cut US proves that circumcision is neither neccessary nor sufficient to prevent cancer. Cancer of the penis is strongly associated with HPV, for which there is now a vaccine.

Quite so, but — returning to the subject — it would be difficult to deny that the risk of penile cancer is greater among uncircumcised males.

Vulval cancer occurs in around 2 women per 100,000, making it at least twice as common as penile cancer, based on UK statistics where few men are circumcised.

By removing the 'extra' skin from girls' vulvae - the labia minora and clitoral hood for example - you will undoubtedly reduce their risk for vulval cancer as there is then less tissue present that may become cancerous in the future.

Think what an impact widespread male and female circumcision could have on HIV rates! It's worked for Africa, hasn't it?

By removing the 'extra' skin from girls' vulvae - the labia minora and clitoral hood for example - you will undoubtedly reduce their risk for vulval cancer as there is then less tissue present that may become cancerous in the future.

This strikes me as a rather dubious assertion. While it's true that removing tissue reduces (well, eliminates) the risk of that tissue becoming cancerous, the effect on the remaining tissue must be considered. For example, scar tissue is generally more likely to be affected, as is tissue with a history of regular inflammation; plausibly these factors might result in increased risk. So really I think it would be sensible to locate some actual studies rather than reasoning on hypothetical grounds.

Think what an impact widespread male and female circumcision could have on HIV rates! It's worked for Africa, hasn't it?

In fact it wouldn't matter TO INFANTS if M or F circumcision eliminated HIV transmission 100% of the time. Condoms can be used until someone is old enough to make an informed decision about the merits of giving up the best part of the genitals.

Those national medical association whose male circumcision policies have been expertly reviewed recently STILL do not endorse routine circumcision, for example Holland's: http://knmg.artsennet.nl/Diensten/knmgpublicaties/KNMGpublicatie/Nontherapeutic-circumcision-of-male-minors-2010.htm

I'm aware of this study; that's why I said that most studies suggest otherwise.

In fact it wouldn't matter TO INFANTS if M or F circumcision eliminated HIV transmission 100% of the time. Condoms can be used until someone is old enough to make an informed decision about the merits of giving up the best part of the genitals.

First, rather than making empty claims it would be sensible for you to provide evidence in support of your assertion that the foreskin is the "best part of the genitals". Second, condoms do not provide complete protection, so your proposal effectively exposes infants to greater risk. Perhaps you find that acceptable, I don't know, but it seems hasty to say that it "wouldn't matter".

provide evidence in support of your assertion that the foreskin is the "best part of the genitals"

My evidence is that I said so. It's my penis. Neither you nor 1000 medical associations can morally own the right to decide for someone else whether any perfectly evolved healthy normal body part is useful or should be discarded. From the most recently revised national medical policy (Holland's) on the subject:

"...The foreskin is regarded as a part of the body that has no function at all in male sexuality. Many sexologists contradict this idea: in their view, the foreskin is a complex, erotogenic structure that plays an important role ‘in the mechanicalfunction of the penis during sexual acts, such as penetrative intercourse and masturbation’."

I'd love to see your evidence for an intervention that is more effective than condoms at preventing HIV transmission among sexually active adults. You're saying that IF the condom fails then someone should be happy they had the additional protection of missing body parts. By your logic we could amputate the whole penis for maximum protection. I'm not trying to be silly. By your logic we could amputate the whole penis for maximum protection. What is reasonable and what is not is for the owner of the penis to decide.

But - and correct me if I'm wrong - you were circumcised as an infant. So your "evidence" that the foreskin is the best part of the penis isn't even anecdotal evidence: it's what you imagine a body part that you lack to be like. It seems a bit of an insult to the intelligence to call that "evidence".

Neither you nor 1000 medical associations can morally own the right to decide for someone else whether any perfectly evolved healthy normal body part is useful or should be discarded.

The attributes of the foreskin are a separate issue from the moral qualities of its removal.

From the most recently revised national medical policy (Holland's) on the subject:

The passage you quote simply refers to the opinions of selected "many sexologists" - which is not evidence. (As it turns out, the "many sexologists" cited turn out to be a single author quoted in an anti-circumcision book!)

I'd love to see your evidence for an intervention that is more effective than condoms at preventing HIV transmission among sexually active adults.

Condoms plus something else?

You're saying that IF the condom fails then someone should be happy they had the additional protection of missing body parts. By your logic we could amputate the whole penis for maximum protection. I'm not trying to be silly.

One of the best ways to prevent HIV is to prevent people from having sex. EVERY study shows that that is an effective way to prevent HIV. So, it seems like instead of circumcising males to get a dubious benefit, we should mutilate females' genitalia to an extent that they can not engage in sex, thus preventing HIV. If we were interested in preventing HIV, clearly we would engage in this rational course of action.

I'm very much against male circumcision but this "study" was horrible. I work in the sciences and have a fairly thorough understanding of these kind of data. In his initial gender-ration estimate he is using the whole infant boy population as well. This means that uncircumcised boys are being used to generate a statistic reflecting apparent circumcision related deaths...it's a statistical nightmare.

I'm considering submitting a formal critique to the journal he was published in. The methodology is flawed, the actually maths are flawed... I actually grabbed the data myself and did some paired t-tests. Not a pretty sight.

Anyway thanks for posting this. It doesn't matter if someone is pro or anti male infant circumcision, there is no excuse for the kind of lazy analysis submitted by Bollinger.

Well I was reading this study and got stuck on the 40.4% part and the related calculations. It didn't look right.

But:

"Clearly, infant mortality rates are consistently higher among males regardless of circumcision rates. So Bollinger's approach is clearly flawed. When he is trying to estimate the risk due to circumcision he is actually estimating the risk due to being male!"

And how are you so sure of it?The infant mortality is calculated over a year period. His 40.4% figure was specifically for the 2.4 days period. And then he refers to deaths during the neonatal period. Of course, it's a risk due to being male for the simple reason that you are comparing the difference between sexes and circumcision itself is one of the risks of being male.

The better methodology would be controlling for all other variables(including nationality) and then a comparison between circumcised and uncircumcised boys.

Thank you for writing this article. I am an avid supporter of circumcisions and its nice to read something that isn't all bias, its nice to have someone clarify a few things for me that others were bashing me about... I would have never tied child deaths to circumcision providing the LARGE number of circumcised males in my family that are all alive, well, and happy without the excess skin, and the numerous diapers I've changed from being a babysitter and a good friend, aunt, niece, cousin, sister, etc. There were nothing wrong with the kids that were circumcised but for the rare few babies that were not the mothers always seemed to complain about them getting UTI's when the circumcised boys mothers never said anything except that for a time after the "cut" they had to make sure to keep the penis cared for and a watchful eye just in case but never had any problems. I would never have a circumcision preformed by anyone that had less than MANY years experience and many procedures under their belt. Just saying... Thanks!

So if it's not evident to novice changing a diaper, it doesn't count as a drawback of circumcising? By that standard there's no end to the list of violent things which could have been done to you as an infant and you'd have no business complaining.

^^ babies that were not {circumcised} the mothers always seemed to complain about them getting UTI's ^^

Fascinating. Do we know anything about these mothers' habits with regards to ill-advised fiddling with the foreskins? Do we know anything about the UTI rates in their daughters?

^^ the circumcised boys' mothers never said anything except that for a time after the "cut" they had to make sure to keep the penis cared for and a watchful eye just in case ^^

So the MOTHERS were happy? Great. How did the penis owners feel when they learned that a portion of their healthy normal pleasure receptive organ was amputated?

^^ I would never have a circumcision preformed by anyone that had less than MANY years experience and many procedures under their belt ^^

Upon whom would you suggest those "warm-up" non-therapeutic amputation procedures be performed?

Jake, I'm circumcised, and I don't think it's some kind of human rights violation to chop that little skin off, nor do I think it's horribly unsafe to leave it on. I'm getting sick of so many over-the-top arguments about every social issue that exists.

To that end, thanks for your clear headed assessments of data. I don't agree with your refutations or counter-factuals 100% of the time (I've read maybe 4 of your posts), indeed everyone's wrong about some things (me too!), but it's nice to find someone who isn't trying to make every point all at once. Refraining from the moral discussion and sticking to public health assessments has made your argument much easier to respect.

That said, I still don't *think* I'll be circumcising my children, as I lean toward the "it's unnecessary surgery" camp. My kid's won't be bangin' aids ladies in the congo... probably.

I do not accept Bollinger's methodology or results. But it is also the case that the tort liability situation in the USA gives hospitals and doctors a very strong financial incentive to code circumcision deaths in ways that are less than truthful. Hence the "official" death rate from circumcision, about 1:500,000, is most likely an understatement. We shall never know for sure until the statute of limitations expires. Even 1:500,000 results in 10-20 deaths per decade, a level I deem unacceptable.

Douglas Gairdner reported in 1949 that British vital statistics recorded that infant circumcision resulted in 10-15 deaths per annum during the 1930s and 40s. These deaths were a major reason why the NHS defunded routine circumcision in 1950.

Having foreskin is not a condition that poses lethal risks, unless the owner of the penis uses it in grossly irresponsible ways. ("Grossly irresponsible" describes the acts that give rise to AIDS and syphilis.) I cannot countenance altering the penis merely to reduce, allegedly, the damage the penis can do when used badly. The most likely consequence of such alteration is more bad behaviour. At any rate, there are no "deaths prevented by circumcision" that can offset the lives lost to circumcision.

And why are the foreskin and frenulum the only parts of the human body to be excised in infancy, for supposedly prophylactic reasons? Why don't we excise that which will develop into the females breasts, given that 80,000+ American women die of breast cancer every year? Because the breasts have considerable value to the women conncected to them, that's why. Likewise, for a goodly number of us intact males and our spouses, the bits circumcision discards likewise have value, and every man should be allowed to decide that value for himself when he attains his majority. This common sense point eludes American neonatal pediatrics, a regrettable situation. But in this curious respect, the USA is unique amongst developed nations.

You said "At any rate, there are no "deaths prevented by circumcision" that can offset the lives lost to circumcision."

I'd question this assertion. AIDS, penile cancer, and UTIs can all be fatal (with varying degrees of probability), and since circumcision reduces the risk of these conditions a certain number of these deaths are ultimately attributable to lack of circumcision.

In fact, it's reasonably easy to show that circumcision can prevent a larger number of deaths due to any one of these conditions than it causes.

Now, please note that I'm not arguing that circumcision should be widely practised in order to prevent these deaths. The actual risk is so small that I think it would be difficult to justify such an argument. But it's time to drop the scare tactic against circumcision - the numbers don't support that argument.